<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>验证码邮件</title>
    <style>
        body {
            font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
            background: #f4f6f9;
            padding: 20px;
        }
        .container {
            max-width: 600px;
            background: #ffffff;
            margin: 0 auto;
            border-radius: 12px;
            box-shadow: 0 4px 12px rgba(0,0,0,0.1);
            overflow: hidden;
        }
        .header {
            background: linear-gradient(90deg, #4e73df, #1cc88a);
            color: #ffffff;
            text-align: center;
            padding: 20px;
            font-size: 22px;
            font-weight: bold;
        }
        .content {
            padding: 30px;
            font-size: 16px;
            color: #333333;
            line-height: 1.6;
        }
        .code {
            font-size: 28px;
            font-weight: bold;
            color: #e74a3b;
            letter-spacing: 6px;
            text-align: center;
            margin: 20px 0;
        }
        .btn {
            display: block;
            width: fit-content;
            margin: 25px auto;
            padding: 12px 30px;
            background: #4e73df;
            color: #ffffff;
            text-decoration: none;
            font-size: 16px;
            border-radius: 8px;
        }
        .footer {
            text-align: center;
            font-size: 12px;
            color: #aaaaaa;
            padding: 15px;
        }
    </style>
</head>
<body>
<div class="container">
    <div class="header">靶场 - 验证码服务</div>
    <div class="content">
        <p>您好，<strong>${username}：</strong></p>
        <p>您正在请求邮箱验证码，请在 <strong>5 分钟</strong> 内使用以下验证码：</p>
        <div class="code">${code}</div>
        <p>如果这不是您的操作，请忽略此邮件。</p>
    </div>
    <div class="footer">
        此邮件由系统自动发送，请勿直接回复。
    </div>
</div>
</body>
</html>
